The inhibition of the corrosion of steel, caused by hydrogen sulfide, was studied at various pH ranges in the presence of an oil phase. Oil-soluble filming amine-type inhibitors are effective in stopping acid corrosion. At 7.7 pH, only two of the oil-soluble inhibitors tested had any effect. At 10 pH, in the presence of cyanide ion, only the water-soluble inhibitors are effective.